There is a need for simplified apparatus capable of accurately measuring and/or mixing different liquids very precisely. The pipette is a common laboratory device for obtaining small samples of liquid which are to be diluted or mixed. Conventional pipettes have the disadvantage of requiring calibration and the further drawback of requiring time consuming, painstaking care in order to achieve accuracy. Moreover, there are inherent safety problems associated with the oral pipetting of certain solutions.
To avoid the necessity of having to use separate pipettes for picking up and dispensing different liquids, a dual-piston syringe was developed which has the capability of sequentially picking up and dispensing two liquids. While this dual-piston syringe has the benefit of accuracy, precision and speed, it lacks the ability to effect mixing or dilution of multiple liquids prior to the time they are dispensed from the syringe.
Certain procedures require that multiple liquids be diluted or mixed in predetermined ratios before being dispensed. Prior to the present invention there was no way of satisfactorily diluting or mixing different liquids in a pipette. Thus, for a uniform mixture to be dispensed from a pipette it was first necessary to premix the liquids in the separate container to obtain a mixture which was then drawn into a pipette from which the mixture could be dispensed. This procedure was both time consuming and wasteful of materials. Furthermore, the required sequence of steps increased the opportunity for contamination of the liquids.